Personality and mood characteristics were studied in epileptic patients before and after unilateral left or right temporal lobectomy. The research examined the role of the limbic system in emotional perception and expression, and how brain injury alters these functions. Left temporal lobectomy (LTL) patients presented an avoidant profile with features of anxiety and dysthymia. Right temporal lobectomy (RTL) patients were overtly expressive, with histrionic features. This pattern is consistent with the hyper-hypoarousal model which accounts for different emotional reactions following left and right brain injury. This also confirms observations made following intracarotid amytal injection where euphoria follows right, and dysphoria, left injection.